If you are running multiple WiFI APs that are part of the same flat network and bridged together it can be tricky keeping a current list of which client is connected to which AP (sometimes clients can just stop responding on one AP and then wake up and appear on another AP). In addition, the one common question a router needs to know is, is this client connected to me OR are they connected through one of my peer routers and which one is the best one?… I wrote a small service which allows an AP to periodically broadcast out, relay/forward, and receive the current WiFi client associations it has and the best association is chosen to amongst all the APs to be able to keep a common set of ARP entries for each access point! The tables are way cleaner and way more consistent with each other now that I have this thing running. I wrote it in both C and python which are supported on OpenWRT routers and can communicate with each other using a common key/pwd. You simply list which radio interfaces the AP has and the IP address you gave the AP on the flat network and it should be ready to send, forward, & receive ARP related messages. The program will write out a standard file with the following information formatted in it and it can also be used with the relayd service modification post below:

/tmp/arp.txt: [dev] [mac/peer] [ip]
wlan1 00:11:22:dd:ee:ff 192.168.100.123

The code can be found here if you are interested!:

C: https://github.com/stoops/broadarp/blob/init/barp.c
Py2: https://github.com/stoops/broadarp/blob/python/barp.py
relayd-mod: https://github.com/stoops/relayd/compare/master…stoops:merged [blog post]

🙂
Jon C